UNASSIGNED: This study investigated seven 1-29-year-old abandoned croplands using the \"space for time\" method in Minqin Oasis. Vegetation succession was classified into different stages using a canonical correlation analysis (CCA) and two-way indicator species analysis (Twinspan). The link between soil properties and vegetation succession was analyzed using CCA. The primary factors shaping community patterns of vegetation succession were chosen by the \"Forward selection\" in CCA. The responses of dominant species to soil properties were analyzed using generalized additive models (GAMs).
UNASSIGNED: Dominant species turnover occurred obviously after cropland abandonment. Vegetation succession can be classified into three stages (i.e., early, intermediate, and late successional stages) with markedly different community composition and diversity. The main drivers of vegetation succession among soil properties were soil salinity and saturated soil water content and they had led to different responses of the dominant species in early and late successional stages. During the development of vegetation succession, community composition became simpler, and species diversity decreased significantly, which was a type of regressive succession. Therefore, measures should be adopted to manage these degraded, abandoned croplands.
■这项研究使用“时空”方法在民勤绿洲调查了7个1-29岁的废弃农田。使用典型相关分析(CCA)和双向指示物种分析(Twinspan)将植被演替分为不同阶段。使用CCA分析了土壤性质与植被演替之间的联系。通过CCA中的“正向选择”选择了影响植被演替群落格局的主要因素。使用广义加性模型(GAMs)分析了优势物种对土壤特性的响应。
■耕地放弃后明显发生了优势种周转。植被演替可分为三个阶段(即,早期,中间,和晚期演替阶段)具有明显不同的群落组成和多样性。土壤特性中植被演替的主要驱动因素是土壤盐分和饱和土壤含水量,它们导致了演替早期和晚期优势种的不同响应。在植被演替的发展过程中,社区组成变得更简单,物种多样性显著下降,这是一种倒退的继承。因此,应采取措施管理这些退化,废弃的农田。